CerefolinNAC® is an orally administered prescription medical food, and is formulated as a combination of L-methylfolate calcium (as Metafolin®), methylcobalamin, and N-acetylcysteine. In a retrospective analysis, disease-delaying effects of Cerefolin®/CerefolinNAC® (CFLN) are examined in terms of cognition (measured by MCI Screen (MCIS)), and functional capacity (measured by Functional Assessment Staging Test (FAST)). - the treatment effect of CFLN on cognitive and functional measures, and on biomarker measures in patients with Alzheimer's disease and related disorders (ADRD).